In general, fabrics such as knitted fabrics or woven fabrics (below to be described commonly as fabrics) that are used to manufacture bed covers, curtains, clothes, etc. are woven by natural fiber yarn or man-made fiber yarn, and their kinds are various, and they have properties and characteristics unique in their own way according to the purpose of use, such as heat conservation, absorptivity, stretchability, etc.
And as industrial society becomes more sophisticated and uses more high technology, modern people demand fabrics having new functions in addition, conventionally, to heat conservation for keeping away coldness, stretachability for ensuring sufficient freedom of motion and absorptivity for absorbing sweat.
For instance, fabrics in demand are those that can conduct electric current for various electric appliances to be installed for convenient use or those that perform heating action or cooling action by themselves. For such fabrics can realize beds, intelligent clothes, etc. which are light and thin and can be used regardless of season.
Accordingly, in the textile industry various efforts and research and development are being made to meet such social demand and lead a future textile industry. As a representative result of research, a planar heating unit made by weaving carbon fiber yarn has been developed.
Such a planar heating unit woven by carbon fiber yarn performs heating action when power is supplied, so it can be applied to the goods that need warming action, but it has a disadvantage that it cannot be applied to bed material that needs a cushioning function or clothes that need stretchability and freedom of motion because it does not have stretchability at all due to the characteristics of carbon fiber yarn. And if friction force is applied continuously while it is being used, the fine structures of carbon fiber yarn become loosened and damaged or minute electrical sparks are generated, so it was not possible to secure sufficient durability and safety.
In addition, smart clothes equipped with electronic appliances such as a wearable computer and an MP3 player need conductive wires for electrically connecting operating buttons, power supply unit, various electronic elements, etc. and for transmitting electric signals, but a planar heating unit manufactured with carbon fiber yarn has a limit that it cannot perform such functions at all. As a way for solving such problems, a method of stitching an extra conductive wire such as copper wire to clothes can be suggested, but because a copper wire does not have any stretchability at all, the freedom of motion and wearability as clothes are not good. Another disadvantage is that it is very inconvenient to use it because the conductive wire and control buttons installed in the clothes have to be removed to wash them.
Accordingly, as a scheme for solving the above mentioned conventional problems, the present applicant has filed Korean Patent Application No. 10-2008-0050545 (title of invention: Electrically conductive pad and manufacturing method thereof), Korean Patent Application No. 10-2008-0128928 (title of invention: Electrically conductive pad), and Korean Patent Application No. 10-2009-0043932 (title of invention: Electrically conductive pad and manufacturing method thereof).
According to these patents, it is possible to make fabrics having stretchability by a method of weaving conductive wires, so it is possible to make them perform heating action without sewing extra conductive wires or realize beds or clothes that can conduct electricity or perform the function of transmitting electric signals.
However, the electrically conductive fabrics that the present applicant earlier filed for a patent therefor has a disadvantage that it is cumbersome to do the work of tying the woven conductive wire together with the fabric yarn into a fabric to configure connection or a circuit with the power supply unit or the work of connecting various elements or modules. In other words, because the worker has to find one by one the electrically conductive wires contained in the fiber yarn configuring electrically conductive woven fabrics to connect each other, it has disadvantages that the work of finding the electrically conductive wires is hard and takes time so as to cause the deterioration of workability and productivity and the fiber yarns nearby are damaged in the course of finding the electrically conductive wires.